For the purpose of sensing such a concealed article, coil-based metal detectors are known in the prior art. Such detectors produce a magnetic field in a measurement region. If there is a metallic article in the measurement region, the article is recognized on the basis of its influence on the magnetic field produced. Frequently, the magnetic field produced is determined by using at least two reception coils which are oriented and connected to one another such that in the absence of a metallic object in the measurement region the measurement signal delivered by both reception coils together is virtually zero (differential measurement). In one variant, a plurality of transmission coils are used to produce the magnetic field, said transmission coils being activated such that the signal measured in the two reception coils is virtually zero regardless of any absence of a metallic object in the measurement region (field-compensated measurement).
DE 10 2007 053 881 A1 describes a measurement method for determining the position or the angle of a coil relative to two further coils. To this end, two transmission coils arranged at an angle relative to one another are used to generate a magnetic alternating field. A reception coil is put into the magnetic alternating field and the actuation of the transmission coils is altered such that the same voltage is induced in the reception coil by each of the transmission coils. A ratio of current values supplied to the transmission coils serves as a measure of determination of the position and/or angle of the reception coil relative to the transmission coils.
DE 10 2004 047 189 A1 describes a metal detector having printed coils.
The disclosure is based on the object of providing simple precise detection for a metallic object. A further object of the disclosure is to specify a method for determining the metallic object.